1. (12 pts) STRESS AND MOHR CIRCLE PRPOBLEM: At depth in a mine, the 3-D stress...

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1. (12 pts) STRESS AND MOHR CIRCLE PRPOBLEM: At depth in a mine, the 3-D stress state has been fully determined so that the three principal compressive stresses are as follows. Draw a physical space cross section of the mine, at approximately the correct depth (assuming 3 is close to the lithostatic stress) and with the 1-03 ellipse drawn in; and a corresponding Mohr circle. Magnitude A 25/210 (plunging 25 to 210) to Orientation 01 500 bars 02 450 bars 03 250 bars (eng S) ( 0/120 (plunging 0 to 120) 65/030 (plunging 65 to 030) a. What is the magnitude of the mean stress in 3D? in 2D in the 01-03 plane? (2 pts) b. What is the magnitude of the differential stress? (2 pts) c. What are the orientations of the planes on which the maximum shear stress acts- give the dip and strike for each plane? (2 pts) d. What is the magnitude of the normal stress and shear stress acting on these planes of maximum shear stress? (2 pts) e. What are the orientations of the planes most likely to form as faults: give the dip and strike for each plane and give the magnitude of the normal stress and shear stress acting on these fault planes (4 pts) f. Comparing values in d and e, and thinking about Mohr-Coulomb failure, why don't faults generally form along the planes of maximum shear stress? Brittle fracture.answer in mohr space 1. (12 pts) STRESS AND MOHR CIRCLE PRPOBLEM: At depth in a mine, the 3-D stress state has been fully determined so that the three principal compressive stresses are as follows. Draw a physical space cross section of the mine, at approximately the correct depth (assuming 3 is close to the lithostatic stress) and with the 1-03 ellipse drawn in; and a corresponding Mohr circle. Magnitude A 25/210 (plunging 25 to 210) to Orientation 01 500 bars 02 450 bars 03 250 bars (eng S) ( 0/120 (plunging 0 to 120) 65/030 (plunging 65 to 030) a. What is the magnitude of the mean stress in 3D? in 2D in the 01-03 plane? (2 pts) b. What is the magnitude of the differential stress? (2 pts) c. What are the orientations of the planes on which the maximum shear stress acts- give the dip and strike for each plane? (2 pts) d. What is the magnitude of the normal stress and shear stress acting on these planes of maximum shear stress? (2 pts) e. What are the orientations of the planes most likely to form as faults: give the dip and strike for each plane and give the magnitude of the normal stress and shear stress acting on these fault planes (4 pts) f. Comparing values in d and e, and thinking about Mohr-Coulomb failure, why don't faults generally form along the planes of maximum shear stress? Brittle fracture.answer in mohr space